1. Field Of The Invention
This invention relates to valve systems of the type adapted to allow the introduction of a surgical instrument into a patient's body. In particular, the invention is applicable to a cannula assembly and the like wherein a cannula extends from a valve assembly and is intended for insertion into a patient's body and an instrument is inserted into the patient's body through the cannula.
2. Background Of The Prior Art
Minimally invasive surgical procedures involve the introduction of surgical instruments into the body through small incisions and/or cannulas or trocar sleeves. Minimally invasive surgical procedures generally require that any instrumentation inserted into the body be sealed, i.e. provisions must be made to ensure that gases do not enter or exit the body through the incision or trocar sleeve as, for example, in surgical procedures in which the surgical region is insufflated. Moreover, minimally invasive surgical procedures often require the surgeon to act on organs, tissues, and vessels far removed from the incision, thereby requiring that any instruments used in such procedures be relatively long and narrow.
For such procedures, the introduction of a tube into certain anatomical cavities such as the abdominal cavity is usually accomplished by use of a system comprised of a cannula assembly and a trocar. A cannula assembly is formed of a cannula or trocar sleeve attached to a valve assembly which is adapted to maintain a seal across the opening of the valve assembly. Since the cannula is in direct communication with the internal portion of the valve assembly, insertion of the cannula into an opening in the patient's body so as to reach the inner abdominal cavity should be adapted to maintain a fluid tight interface between the abdominal cavity and the outside atmosphere.
Since minimally invasive surgical procedures in the abdominal cavity of the body require insufflating gases to raise the cavity wall away from vital organs, the procedure is usually initiated by use of a Verres needle through which a gas is introduced into the body cavity. Thereafter, a trocar, which is a sharp pointed instrument, is inserted into the cannula assembly and used to puncture the peritoneum, i.e. the inner lining of the abdominal cavity wall. The gas provides a slight pressure which raises the wall surface of the peritoneum away from the vital organs, thereby avoiding unnecessary contact with the organs by the instruments inserted into the cannula. This procedure also provides the surgeon with an adequate region in which to operate. Laparoscopic or endoscopic surgical instruments may then be inserted through the cannula to perform surgery within the abdominal cavity or other body portion. The cannula is also utilized for introducing tubes into the body as for drainage purposes or the like.
In view of the need to maintain the atmospheric integrity of the inner area of the cavity, a valve assembly which permits introduction of a trocar or any surgical instrument and which permits selective communication of the inner atmosphere of the cavity with the outside atmosphere is desirable. In this regard, there have been a number of attempts in the prior art to provide such atmospheric integrity.
U.S. Pat. No. 5,180,373 to Green et at. discloses a unique valve assembly which may be incorporated into a cannula assembly or utilized in combination with any type of tubular member for introduction into the body of a patient while permitting introduction of instruments into the body. The assembly disclosed in the Green et at. '373 patent includes a first valve formed of a resilient material and defining an aperture for reception of the object and a second valve positioned adjacent and distal of the first valve in general alignment therewith and defining an aperture in general alignment with the aperture of the first valve. A pair of manually operable clamps is provided to selectively permit the aperture of the second valve to be opened or closed so as to permit entry of the object such that the object first passes through the first valve and then the second valve prior to entry into the patient's body. The manually operable clamps enable the surgeon to selectively open or close the second valve in sequence and in a manner which positively retains the desired interface between the atmosphere on the inlet side of the valve assembly and the atmosphere outside the valve assembly.
Although the valve assembly disclosed in the Green et at. '373 patent is effective for its intended purpose, the present invention is directed to another unique valve assembly for use in combination with a cannula assembly whereby opening of the valve mechanism for permitting entry of the surgical instrument may be readily achieved with an enhanced degree of control, i.e., by the rotation of a single control knob.